Enhanced Oil Recovery (EOR) is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field. The term Enhanced Gas Recovery (EGR) is a generic term for techniques for increasing the amount of natural gas that can be extracted e.g. from a nearly depleted gas field. There currently are several different methods of Enhanced Oil Recovery including steam flood and water flood injection and hydraulic fracturing. Enhanced oil recovery extraction methods consume large quantities of water, natural gas and energy. Gas injection or miscible flooding is presently the most-commonly used approach in enhanced oil recovery. The fluid most commonly used for miscible displacement is carbon dioxide because it reduces the oil viscosity and is less expensive than liquefied petroleum gas. Carbon dioxide is particularly effective in reservoirs deeper than 600 m, where carbon dioxide will be in a supercritical state. In high pressure applications with lighter oils, carbon dioxide is miscible with the oil, with resultant swelling of the oil, and reduction in viscosity. Carbon Dioxide as a solvent has the benefit of being more economical than other similarly miscible fluids such as propane and butane.
Document US2006/0115691A1 discloses a method for exhaust gas treatment in a solid oxide fuel cell power plant with carbon dioxide capture, in which the unreacted fuel in the anode exhaust is recovered and recycled, while the resulting exhaust stream consists of highly concentrated carbon dioxide. One disadvantage of this method is that the method is less energy-efficient so that additional resources and products are needed to run the process. In addition this method is limited to a pressurized SOFC system only.
Document US2010/0266923A1 discloses a fuel cell system comprising an electrochemical hydrogen pump comprising a proton exchange membrane. A water-gas shift (WGS) reaction catalyst is incorporated within the electrochemical hydrogen pump. This embodiment allows a high rate of fuel recirculation, which means a recirculation of hydrogen, to obtain a high overall fuel utilization, which results in a high system efficiency. The hydrogen separation device is used to enrich the recirculated portion of anode exhaust stream with hydrogen by electrochemically pumping hydrogen out of the SOFC stack anode exhaust stream. Operation of such a fuel cell system allows for SOFC fuel utilization rates approaching 100%. To reach such high SOFC fuel utilization rates, the electrochemical hydrogen pump must be operated in excess of 90% utilization. This means that at least 90% of hydrogen in the SOFC stack anode exhaust stream has to be separated and recycled. Under these conditions, the SOFC system may be operated with at least 96% fuel utilization and most preferably with about 99% fuel utilization. One disadvantage of this system is that it is optimized for high fuel utilization and is therefore not suitable as a hydrogen generator with carbon dioxide capture.